Irreversible interactions between water and DGEBA/DDA epoxy resin during hygrothermal aging

Abstract

Two approaches were adopted to examine the irreversible interactions between water and a model epoxy resin (DGEBA/DDA). One was to employ XPS to investigate the changes of the chemical structure of the resin after immersion in water at a temperature of 90ЊC and followed by completely drying. The other was to use XPS and FTIR to characterize the degradation products formed during hygrothermal aging. The results clearly showed that irreversible interactions occurred between water and the resin at elevated temperature. Water can lead to the incorporation of C{O and N{CO{N groups in the resin and cut the epoxy backbone chain. Based on the results obtained, a tentative degradation mechanism is proposed and found to explain the results reasonably well.

Equilibrium moisture content of a crosslinked epoxy network via molecular dynamics simulations

“…However, the thermomechanical properties of epoxy resins are known to be strongly influenced by environmental factors. Experimentally, these issues have been studied extensively [1][2][3][4], providing several hypotheses about the interactions between water and epoxy resins. Most commonly, results indicate that the properties of the system degrade due to plasticization in the resin caused by the presence of water.…”

Experimental and numerical investigation of the static response of environmentally aged adhesively bonded joints

“…The bound water generally occurs with increasing exposure time or temperature, and can disrupt the molecular chain structure to induce irreversible degradation [11,12]. Leaching from the disrupted chain network, and possibly the filler, may further degrade the bulk adhesive [9,[13][14][15].…”

Environmental aging of cold‐cured epoxy‐silica hybrids prepared by sol−gel process

“…For such a reason, these epoxybased hybrid systems have been investigated by the authors as potential "cold-cured" adhesives, i.e. 24 The lowering of the T g due to water ingress into epoxy resins can be particularly harmful for cold-curing epoxies whose typical T g is not much higher than the service temperature. 14 To the best of our knowledge, there are no studies in literature on the evaluation of epoxy hybrids as cold-cured adhesives, apart from recent works of the authors.…”